We investigate numerically the sedimentations of solid particles in a fluid with different temperatures using a lattice Boltzmann method. The sedimentation processes of a single particle in an isothermal, hot, or cool fluid are first simulated, and then the sedimentations of two particles with different temperatures are carefully studied. It is found that the dynamics of the two particles with the same temperature is closely related to the Reynolds number and the Grashof number, while the process of two particles with different temperatures are different from that of two particles with the same temperature. The cold particle will eventually descend under the hot particle, and the drafting and kissing phenomenon occurs as Re is large, while the cold particle falls far from the hot one as Re is small.